Neigong exercises that are part of the neijia tradition involve cultivating physical stillness and or conscious (deliberate) movement, designed to produce relaxation or releasing of muscular tension combined with special breathing techniques such as the "tortoise" or "reverse" methods.
The fundamental purpose of this process is to develop a high level of coordination, concentration and technical skill that is known in the martial arts world as neijin (內勁).
One of the benefits of martial neigong exercises is the relaxation of blood vessels, nerves, muscles and sinews to help the body move more freely.
It is rare to learn authentic Daoist practices from a true master of the subject as quite a lot of the neigong skills are an essential part of a complete system of martial arts.
There are intellectual guidelines to the practice of neigong, but it is "Inner Work" which means effort has to be put in to develop real, substantial and testable skills.